[libpng15] Updated contrib/sRGBtables code
diff --git a/contrib/sRGBtables/cvtcolor.c b/contrib/sRGBtables/cvtcolor.c
new file mode 100644
index 0000000..26afe6d
--- /dev/null
+++ b/contrib/sRGBtables/cvtcolor.c
@@ -0,0 +1,181 @@
+/*-
+ * convert.c
+ *
+ * Convert 8-bit sRGB or 16-bit linear values to another format.
+ */
+#define _ISOC99_SOURCE 1
+
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <stdio.h>
+
+#include <fenv.h>
+
+#include "sRGB.h"
+
+static void
+usage(const char *prog)
+{
+ fprintf(stderr,
+ "%s: usage: %s [-linear|-sRGB] [-gray|-color] component{1,4}\n",
+ prog, prog);
+ exit(1);
+}
+
+unsigned long
+component(const char *prog, const char *arg, int issRGB)
+{
+ char *ep;
+ unsigned long c = strtoul(arg, &ep, 0);
+
+ if (ep <= arg || *ep || c > 65535 || (issRGB && c > 255))
+ {
+ fprintf(stderr, "%s: %s: invalid component value (%lu)\n", prog, arg, c);
+ usage(prog);
+ }
+
+ return c;
+}
+
+int
+main(int argc, const char **argv)
+{
+ const char *prog = *argv++;
+ int to_linear = 0, to_gray = 0, to_color = 0;
+ int channels = 0;
+ double c[4];
+
+ /* FE_TONEAREST is the IEEE754 round to nearest, preferring even, mode; i.e.
+ * everything rounds to the nearest value except that '.5' rounds to the
+ * nearest even value.
+ */
+ fesetround(FE_TONEAREST);
+
+ c[3] = c[2] = c[1] = c[0] = 0;
+
+ while (--argc > 0 && **argv == '-')
+ {
+ const char *arg = 1+*argv++;
+
+ if (strcmp(arg, "sRGB") == 0)
+ to_linear = 0;
+
+ else if (strcmp(arg, "linear") == 0)
+ to_linear = 1;
+
+ else if (strcmp(arg, "gray") == 0)
+ to_gray = 1, to_color = 0;
+
+ else if (strcmp(arg, "color") == 0)
+ to_gray = 0, to_color = 1;
+
+ else
+ usage(prog);
+ }
+
+ switch (argc)
+ {
+ default:
+ usage(prog);
+ break;
+
+ case 4:
+ c[3] = component(prog, argv[3], to_linear);
+ ++channels;
+ case 3:
+ c[2] = component(prog, argv[2], to_linear);
+ ++channels;
+ case 2:
+ c[1] = component(prog, argv[1], to_linear);
+ ++channels;
+ case 1:
+ c[0] = component(prog, argv[0], to_linear);
+ ++channels;
+ break;
+ }
+
+ if (to_linear)
+ {
+ int i;
+ int components = channels;
+
+ if ((components & 1) == 0)
+ --components;
+
+ for (i=0; i<components; ++i) c[i] = linear_from_sRGB(c[i] / 255);
+ if (components < channels)
+ c[components] = c[components] / 255;
+ }
+
+ else
+ {
+ int i;
+ for (i=0; i<4; ++i) c[i] /= 65535;
+
+ if ((channels & 1) == 0)
+ {
+ double alpha = c[channels-1];
+
+ if (alpha > 0)
+ for (i=0; i<channels-1; ++i) c[i] /= alpha;
+ else
+ for (i=0; i<channels-1; ++i) c[i] = 1;
+ }
+ }
+
+ if (to_gray)
+ {
+ if (channels < 3)
+ {
+ fprintf(stderr, "%s: too few channels (%d) for -gray\n",
+ prog, channels);
+ usage(prog);
+ }
+
+ c[0] = YfromRGB(c[0], c[1], c[2]);
+ channels -= 2;
+ }
+
+ if (to_color)
+ {
+ if (channels > 2)
+ {
+ fprintf(stderr, "%s: too many channels (%d) for -color\n",
+ prog, channels);
+ usage(prog);
+ }
+
+ c[3] = c[1]; /* alpha, if present */
+ c[2] = c[1] = c[0];
+ }
+
+ if (to_linear)
+ {
+ int i;
+ if ((channels & 1) == 0)
+ {
+ double alpha = c[channels-1];
+ for (i=0; i<channels-1; ++i) c[i] *= alpha;
+ }
+
+ for (i=0; i<channels; ++i) c[i] = nearbyint(c[i] * 65535);
+ }
+
+ else /* to sRGB */
+ {
+ int i = (channels+1)&~1;
+ while (--i >= 0)
+ c[i] = sRGB_from_linear(c[i]);
+
+ for (i=0; i<channels; ++i) c[i] = nearbyint(c[i] * 255);
+ }
+
+ {
+ int i;
+ for (i=0; i<channels; ++i) printf(" %g", c[i]);
+ }
+ printf("\n");
+
+ return 0;
+}
diff --git a/contrib/sRGBtables/makesRGB.c b/contrib/sRGBtables/makesRGB.c
index ac08d3e..41ca27a 100644
--- a/contrib/sRGBtables/makesRGB.c
+++ b/contrib/sRGBtables/makesRGB.c
@@ -23,37 +23,9 @@
/* pngpriv.h includes the definition of 'PNG_sRGB_FROM_LINEAR' which is required
* to verify the actual code.
*/
-#include "../pngpriv.h"
+#include "../../pngpriv.h"
-/*
- * Utility sRGB calculation functions.
- *
- * Both routines take and return a floating point value in the range
- * 0 to 1.0, doing a calculation according to the sRGB specification.
- * (In fact the source of the numbers is the wikipedia article at
- * http://en.wikipedia.org/wiki/SRGB .)
- */
-double
-sRGB_from_linear(double l)
-{
- if (l <= 0.0031308)
- l *= 12.92;
-
- else
- l = 1.055 * pow(l, 1/2.4) - 0.055;
-
- return l;
-}
-
-double
-linear_from_sRGB(double s)
-{
- if (s <= 0.04045)
- return s / 12.92;
-
- else
- return pow((s+0.055)/1.055, 2.4);
-}
+#include "sRGB.h"
/* The tables are declared 'const' in pngpriv.h, so this redefines the tables to
* be used.
diff --git a/contrib/sRGBtables/sRGB.h b/contrib/sRGBtables/sRGB.h
index 5e83e1a..a4332d8 100644
--- a/contrib/sRGBtables/sRGB.h
+++ b/contrib/sRGBtables/sRGB.h
@@ -4,9 +4,10 @@
* Utility file; not actually a header, this contains definitions of sRGB
* calculation functions for inclusion in those test programs that need them.
*
- * All routines take and return a floating point value in the range 0 to 1.0,
- * doing a calculation according to the sRGB specification. (In fact the source
- * of the numbers is the wikipedia article.)
+ * All routines take and return a floating point value in the range
+ * 0 to 1.0, doing a calculation according to the sRGB specification
+ * (in fact the source of the numbers is the wikipedia article at
+ * http://en.wikipedia.org/wiki/SRGB).
*/
static double
sRGB_from_linear(double l)
